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I keep getting this error (I'm using Visual C++ 2005 Express Edition by the way):
error C2440: '=' : cannot convert from 'void *' to 'ListNodePtr'
Code:/* Operating and maintaining a list */ #include<stdio.h> #include<stdlib.h> /* self-referential structure */ struct listNode { char data; /* each listNode contains a character */ struct listNode *nextPtr; /* pointer to next node*/ }; /* end structure listNode */ typedef struct listNode ListNode; /* synonym for struct listNode */ typedef struct listNode *ListNodePtr; /* synonym for ListNode* */ /* prototypes */ void insert( ListNodePtr *sPtr, char value ); char del( ListNodePtr *sPtr, char value ); int isEmpty( ListNodePtr sPtr ); void printList( ListNodePtr currentPtr ); void instructions( void ); int main( void ) { ListNodePtr startPtr = NULL; /* initially there are no nodes */ int choice; /* user's choice */ char item; /* char entered by user */ instructions(); /* display the menu */ printf("? "); scanf_s("%d", &choice); /* loop while user does not choose 3 */ while ( choice != 3 ) { switch ( choice ) { case 1: printf( "Enter a character: " ); scanf_s( "\n%c", &item ); insert( &startPtr, item ); /* insert item in list */ printList( startPtr ); break; case 2: /* if list is not empty */ if ( !isEmpty( startPtr ) ) { printf( "Enter character to be deleted: " ); scanf_s( "\n%c", &item ); /* if character is found, remove it */ if ( del( &startPtr, item ) ) { /* remove item */ printf( "%c deleted.\n", item ); printList( startPtr ); } /* end if */ else { printf( "%c not found.\n\n", item ); } /* end else */ } /* end if */ else { printf( "List is empty.\n\n" ); } /* end else */ break; default: printf( "Invalid choice.\n\n" ); instructions(); break; } /* end switch */ printf( "? " ); scanf_s( "%d", &choice ); } /* end while */ printf( "End of run.\n" ); return 0; /* indicates successful termination */ } /* end main */ /* display program instructions to user */ void instructions( void ) { printf( "Enter your choice:\n" " 1 to insert an element into the list.\n" " 2 to delete an element from the list.\n" " 3 to end.\n" ); } /* end function instructions */ /* Insert a new value into the list in sorted order */ void insert( ListNodePtr *sPtr, char value ) { ListNodePtr newPtr; /* pointer to new node */ ListNodePtr previousPtr; /* pointer to previous node in list */ ListNodePtr currentPtr; /* pointer to current node in list */ newPtr = malloc( sizeof(ListNode) ); /* create node */ <- this is where I start getting the error if ( newPtr != NULL ) { /* is space available */ newPtr->data = value; /* place value in node */ newPtr->nextPtr = NULL; /* node does not link to another node */ previousPtr = NULL; currentPtr = *sPtr; /* loop to find the correct location in the list */ while ( currentPtr != NULL && value > currentPtr->data ) { previousPtr = currentPtr; /* walk to ... */ currentPtr = currentPtr->nextPtr; /* ... next node */ } /* end while */ /* insert new node at beginning of list */ if ( previousPtr == NULL ) { newPtr->nextPtr = *sPtr; *sPtr = newPtr; } /* end if */ else { /* insert new node between previousPtr and currentPtr */ previousPtr->nextPtr = newPtr; newPtr->nextPtr = currentPtr; } /* end else */ } /* end if */ else { printf( "%c not inserted. No memory available.\n", value ); } /* end else */ } /* end function insert */ /* Delete a list element */ char del( ListNodePtr *sPtr, char value ) { ListNodePtr previousPtr; /* pointer to previous node in list */ ListNodePtr currentPtr; /* pointer to current node in list */ ListNodePtr tempPtr; /* temporary node pointer */ /* delete first node */ if ( value == ( *sPtr )->data ) { tempPtr = *sPtr; /* hold onto node being removed */ *sPtr = ( *sPtr )->nextPtr; /* de-thread the node */ free( tempPtr ); /* free the de-threaded node */ return value; } /* end if */ else { previousPtr = *sPtr; currentPtr = ( *sPtr )->nextPtr; /* loop to find the correct location in the list */ while ( currentPtr != NULL && currentPtr->data != value ) { previousPtr = currentPtr; /* walk to ... */ currentPtr = currentPtr->nextPtr; /* ... next node */ } /* end while */ /* delete node at currentPtr */ if ( currentPtr != NULL ) { tempPtr = currentPtr; previousPtr->nextPtr = currentPtr->nextPtr; free( tempPtr ); return value; } /* end if */ } /* end else */ return '\0'; } /* end function delete */ /* Return 1 if the list is empty, 0 otherwise */ int isEmpty( ListNodePtr sPtr ) { return sPtr == NULL; } /* end function isEmpty */ /* Print the list */ void printList( ListNodePtr currentPtr ) { /* if list is empty */ if ( currentPtr == NULL ) { printf( "List is empty.\n\n" ); } /* end if */ else { printf( "The list is:\n" ); /* while not the end of the list */ while ( currentPtr != NULL ) { printf( "%c --> ", currentPtr->data ); currentPtr = currentPtr->nextPtr; } /* end while */ printf( "NULL\n\n" ); } /* end else */ } /* end function printList */
Originally Posted by We'reGeeks 
